The author didn't say so, but I'd assume these sensors must be placed in a small oven of some kind, so as to introduce averaging and hysteresis of temperature.

The author didn't say so, but I'd assume these sensors must be placed in a small oven of some kind, so as to introduce averaging and hysteresis of temperature. When I brew my beer, I need to look at the environmental temperature. I can't stick the thermometer in the beer because it'll be contaminated. So I put a thermometer in a glass of water which I place next to the beer vat. I'd expect you'd have to put that BME280 in a small metal oven, or submerge in a volume of oil or water. It'll screw up the barometer probably.